John fleming-



Pate n t e' i UNITED STATES PATENT FFICE.

JOHN FLEMING, OF SPRING CITY, ASSIGNOR TO HIMSELF, OLIVER B. KEELEY, OF SAME PLACE, AND ENOS S. SHANTZ, OF PHILADELPHIA, PA.

R K o R L L BIT.

SPECIFICATION forming part of Letters Patent No. 224,412, dated February 10, 1880.

Application filed December 15, 1879.

' To all whom it may concern Be it know n that I, JOHN FLEMING, of Spring City, Chester county, Pennsylvania, have invented a new and useful Improvement in Rock- Drill Bits, of which the following is a specification.

My invention consists of a rock-drill hit 0011- stru oted with curved cutting-edges and channels, in the peculiar manner fully described hereinafter, in order to insure a more rapid and effective action of the bit on the rock than that resulting from the use of ordinary drillin g-tools.

In the accompanying drawings, Figure 1 is I 5 a side view of the lower portion of the rockdrill bit; Fig. 2, a vertical section on the line 1 2; Fig. 3, a vertical section 011 the line 3 and Fig. 4, an inverted plan view of the bit,

point, 1). These two portions a a of the cutting-edge are beveled on one side only, the edge of the portion a being beveled in the direction of the arrow 1 and that of the portion a. in the direction of the arrow 2, Fig. 4. Each beveled edge merges into the bottom of a channel, d, formed in the tapering portion of the bit, as shown in Figs. 2 and 3, the two channels being deep at the lowerend of the bit, and becoming gradually shallower as they ascend until they disappear at their upper ends in the cylindrical shank.

It will be seen that the cutting-edge of this bit is more extended than the straight-edges of ordinary rook-drilling tools. My improved 0 drill, moreover, must necessarily out a clean hole in the rock--that is, a hole with smoother sides than one out by an ordinary drill and in practice ithas been found that the drill is more rapid and etficient in its action-a result 5 attributable, it is believed, partly to the shape the drill-rod falls that the said detritus cannot materially lessen the effect of the blow of the cutting-edge on the rock. I claim as my invention The within-described rock-drill bit having a cutting-edge made on two curves, a a, meeting each otherat the central point, 1), the edge within the limit of one curve being beveled on one" side and in one direction and merging into the bottom of a channel, 61, and the edge within the limits of the other portion of the curve being beveled on one side, but in a contrary direction, and merging into the bottom of another and similar channel, all substantially as set forth.

In, testimony whereof I have. signed my name to this specification in the presence of two subscribing witnesses.

, JOHN FLEMING.

Witnesses:

IRWIN WELLS, (3120. W. FLOYD, 

